"While it’s true that current natural gas prices beat the cost of operating air source heat pumps. The heat pumps still beat the cost of oil or propane (and wood) heating by quite a lot! http://www.efficiencymaine.com/at-home/home-energy-savings-program/heating-cost-comparison/.
Moreover, converting more of our heating load to air source heat pumps matches a national trend. Only the Northeast is still increasing use of natural gas for home heating."